She was born during her father's tenure as ambassador to the Ottoman Empire, which her mother wrote about in her Letters from Turkey.

On 24 August 1736, she married John Stuart, 3rd Earl of Bute, who became the prime minister of Great Britain in 1762.

[1] The couple had five sons and six daughters,[1] including: In 1761, she was created Baroness Mount Stuart, of Wortley in the county of York, with a remainder to her male heirs by her husband.

In 1774, Mary Delany wrote to her brother Bernard Granville, Jacobite Duke of Albemarle, saying: "You know so much of Lady Bute that I need say nothing of her agreeableness, her good sense, and good principles, which with great civility must be always pleasing.

"[5] Writing for the Oxford Dictionary of National Biography, Karl Wolfgang Schweizer said that: "Lady Bute seems to have been a woman of prudence, loyalty, and tact, greatly devoted to her husband and family.